US2020649A - Treatment of hydrocarbons - Google Patents

Description

Patented Nov. 12, 1935 UNITED STATES PATENT OFFICE No Drawing. Application July 3, 1933, Serial No. 678,931

12 Claims. (01. 196-10) This invention relates more particularly .to the treatment of olefinic hydrocarbons which are normally gaseous at ordinary temperatures and pressures.

Olefinic hydrocarbons with which the present invention is concerned occur along with corresponding paraflinic or saturated hydrocarbons in commercial hydrocarbon mixtures such as those encountered in the cracking of petroleum, in gas making processes and as by-products in various chemical industries. In general they are more chemically active than other classes of hydrocarbons, particularly if they contain more than one double bond or triple bonds between carbon atoms. Even when under mild catalytic influence they exhibit this reactivity in their pronounced tendency to polymerize and form substances of higher molecular weight.

Olefins occur in particularly large percentages in the fixed gases from cracking processes as well as in the gasoline boiling range fractions. The fixed gases are utilizedprincipally as fuel, only a very small percentage of present day com- The present process provides for more effectively utilizing the olefinic constituents of commercial hydrocarbon mixtures particularly those occurring in the gases from oil cracking processes to produce valuable derivatives therefrom and it may also be applied to individual olefms produced by special chemical methods or by fractionation of mixtures.

In one specific embodiment the invention comprises treatment of normally gaseous olefin hydrocarbons at elevated temperatures to produce polymers therefrom utilizable as constituents of motor fuel with solid contact materials or catalysts comprising phosphoric acid, zinc chloride or zinc oxide and spacing or carrying materials of a porous or adsorptive character.

In a further specific embodiment, both zinc chloride and zinc oxide may be included in the catalyst mass.

The following table is introduced to show the general character of the compounds treated by the present process. It is not complete but is introduced as a matter of reference.

Compounds Formula o gf t y ne CH CH -105 Propylene- CH=CH=CH1 4 Ethyl ethylene. CH;QH,CH=0H, ii gf fi-bimemyl ethy CH=-OH=CH-CH: +15 Unsym. dimethyl ethylene (CH3) C=CH 6 n-propyl ethylene (a-amylene CH3CHzCH2CH=CHz +39 lsopropyl ethylene (a-isoamy ene) (CHs)zCH-CH=CH2 Sym. methyl ethyl ethylene (fl-amylene) CH3-CH1-CH=OH-GH:+ Unsym. methyl ethyl ethylene (rainylene) CHs-GHI C=CH1.- +31 Trim th 1 m 1 am 1 (CH)% CH on +36 e y e yene yene H a Tetramethyl ethy +78 mercial production being subjected to processes for the recovery or utilization of the olefinic constituents. The manufacture of secondary alcohols such as iso-propyl alcohol and others byflrst absorbing the corresponding olefins in cracked gases in sulfuric acid and then hydrolyzing the acid esters has been undertaken to a limited extent. The oleflns present in cracked hydrocarbon mixtures of gasoline boiling range are of moderately high anti-knock value, but a certain percentage of these is too highly unsaturated, and these must be removed by chemical treatment, usually with sulfuric acid to insure proper stability of the gasoline under storage conditions.

The boiling points given in the table indicate that the four carbon atom members are gaseous at ordinary temperatures-and that the five carbon atom members may readily exist in minor proportions in commercial gas mixtures, such as the cracked hydrocarbon gas mixtures with which the present invention is specially concerned.

The present process is particularly directed.

to ,the production of dimers and trimers from mono-olefins, particularly such olefins whose been found that the dimers and some of the triwhich will occur in appreciable quantities in the gases from oil cracking processes.

Boiling points of olefin dimers F. Hexylene Octylene 255 Decylene 323 Dodecylene 417 Of the lower boiling and normally gaseous olefins, ethylene is the most resistant to polymerization by catalysts of the present character, but in the presence of its higher homologs it is probable that a certain amount of mixed polymers are 'formed.

Polymers of higher molecular weight than the diand tri-molecular compounds are generally of too high boiling point to be used in commercial gasolines and the end products of too extensive polymerization are resinous pitchy solids which are entirely'unsuitable.

The essential ingredients of the catalyst mixtures whose use constitutes the main feature of the invention are phosphoric acid and zinc chlo ride or oxide, the orthophosphoric acid HzPO4 being generally preferred on account of its ready availability although other acids of phosphorus may also be employed. As a rule the phosphoric acid constitutes the major portion of these essential ingredients, which are preferably incorporated with substantial amounts of spacing or carrying materials of a generally porous character or which develop a porous character under proper heat treatment, so that the effectiveness of the preferred catalysts in inducing and accelerating polymerization among gaseous olefins is particularly high.

The spacing or carrying materials which may be employed may be divided roughly into three general classes:

(1) Siliceous qr aluminous materials of an active character which exert a variable promoting action as a component of the catalytic mass. This class includes such materials as activated alumina, the mineral bauxite, fullers earth, bentonite and other selected clays, kieselguhr or infusorial earth, and some artificially prepared forms of silica or aluminum silicates. The influence of different materials of this. character on the activity of the total catalyst mixture will depend upon their individual characteristics and their physicalcondition, particularly in regard to porosity, and each substance will exert its own individual effect when employed alternatively which is not exactly equivalent to the other materials which may be employed.

(2) Materials of an essentially siliceous character which have substantially no catalytic or promoting action but which function principally as carriers and in strengthening the catalyst structure. This class includes such materials as fire clays, silica fragments of varying fineness, pumice, etc., which may be used alternatively depending upon which is at hand in greatest quantity. These materials have substantially no reactivity with phosphoric acid and consequently do not yield phosphates.

(3) Organic materials which yield some type preheated to a suitable temperature prior to pasof carbonaceous residue on heating. This class includes such materials as cellulose, starches, sugars, glue, gelatin, flour, molasses, agar-agar, et cetera. They evidently function as binders in increasing the strength and resistance to disin- 5 tegration of the contact masses in service.

Catalysts of the character comprised withinthe scope of the present invention are producible by a series of relatively simple steps comprising generally: mixing the constituents in the selected proportions, drying by heating at temperatures of approximately to 220 C. and grinding and sizing the resultant product to particles of the desired size. When carbonaceous materials are used somewhat higher temperatures may be em- 1 ployed to decompose them. Good results have been obtained at 300 C. and in some instances it would appear that too high temperatures above this point have deleterious effect. The exact maximum temperature employed in the ignition 20 step will be to some extent a matter of trial.

Catalysts of the present character are hygroscopic to a variable extent and are best ground, sized and preserved for use out of contact with moist air. 25

Owing to the possibilities of varying the ingredients which go to form the catalyst masses,

a number of alternatives exist,-each of which will have its own peculiar catalyzing and polymerizing character, which will not be exactly 30 equivalent to masses of different composition.

The polymerizing of gaseous olefins with such catalysts may be brought about under numerous combinations of temperature and pressure, though the best results for any given pure olefin 5 or mixture of olefins such as those encountered in the gases from oil cracking plants, will usually correspond to a particular set of conditions. It is a feature of the present type of catalyst that treatments may be conducted at temperatures as 40 high as 250 C. and superatmospheric pressures up to several hundred pounds per square inch without danger of over-polymerization resulting in the formation of heavy tar-like polymers instead of liquids of gasoline boiling range. 45

In using the catalysts only simple equipment is necessary such as a tube or tower in which the catalyst is placed as a filling material. The gases may be pumped up to some given pressure and sage through the" catalyst mass or the catalyst chamber may be heated externally if desired. A few test runs will usually determine the best conditions of operation. For example, if the temperatures and pressures employed are such that 55 the products exist in vapor phase, the flow of the gases-through the catalyst may be upward through filled towers, while if liquids are condensed, the best results may be obtained when down flows are used so that liquid does not ac- 60 cumulate on the surface of the catalyst.

Catalysts of the present type are characterized by their ability to polymerize olefins to produce relatively low boiling hydrocarbon polymers rather than heavy tars or pitches and by their 65 long life due to the absence of such highly carbonaceous reaction products and also due to lack of oxidizing tendency in the phosphoric acid which constitutes the major portion thereof. In contrast to this it is notable that when employing sulfuric acid as a polymerizing agent, caution is necessary to prevent oxidation and undesirable side reactions such as ester formation and that, when employing metal halides such as aluminum chloride or zinc chloride alone, the tendency to- 75 the fact that they are substantially of a non-- corrosive character owing to the partial neutralization of the phosphoric acid and the formation of acid phosphates.

The following example is given to show the results obtainable with a catalyst whose composition corresponds to those covered by the present invention. This is merely one isolated instance and a number of others are available.

The catalyst employed was made using:

Parts by weight 89% phosphoric acid -1 495 Zinc oxide 41 Zinc chlor de 68 Aluminum hydrate 50 The exact procedure in making up this catalyst was as follows: A paste was made by stirring together 41 parts by weight of zinc oxide, 68 parts by weight of powdered zinc chloride and 495 parts by weight of 89% phosphoric acid. The mass was still mobile after standing 15 hours, at room temperature and was boiled for two hours at a temperature of from 185 to 208 C. 50 parts by weight of aluminum hydrate was then stirred into the boiling mixture, forming a stiff paste. This paste was dried in air for 36 hours at a temperature of from 180 to220 C., during which time 150 parts by weight of water was evolved. After cooling, the dried white solid material was ground and sized to produce a. catalyst mass consisting of particles between 6 and 20 mesh. The following table shows the results obtained tion of efliciency and this figure does not represent the limit yield.

The foregoing specification and example have shown the character of the invention and results obtainable by its use respectively but neither is 5 to be construed in the light of imposing undue limitations thereon.

I claim as my invention:

1. A process for the treatment of normally gaseous olefin hydrocarbons to convert the same into 10 liquid hydrocarbons suitable for motor fuel which comprises, subjecting said gaseous olefin hydrocarbons while at elevated temperatures to the action of a contact agent comprising, phosphoric acid, aluminum oxide, zinc oxide and zinc 15 chloride.

2. A process for the treatment of normally gaseous olefin hydrocarbons to convert the same into liquid hydrocarbons suitable for motor fuel which comprises, subjecting said gaseous olefin hydro- 20 carbons while at elevated temperature to the action of a contact agent comprising, phosphoric acid, zinc oxide and zinc chloride.

3. A process for the treatment of normally gaseous olefin hydrocarbons to convert the same into 25 liquid hydrocarbons suitable for motor fuel which comprises, subjecting said gaseous olefin hydrocarbons while at elevated temperature to the action of a contact agent comprising, phosphoric acid and zinc oxide.

4. A process for the treatment of normally gaseous olefin hydrocarbons to convert the same into liquid hydrocarbons suitable for motor fuel which comprises, subjecting said gaseous olefin hydrocarbons while at elevated temperature to the 35 action of a contact agent comprising, phosphoric acid and zinc chloride.

5. A process for the treatment of normally gaseous olefin hydrocarbons to convert the same into liquid hydrocarbons suitable for motor fuel which 40 comprises, subjecting said gaseous olefin hydrocarbons while at elevated temperature, above 100 C., and below 250 C., to the action of a contact agent comprising, phosphoric acid, aluminum The composite sample of the liquidproduced contains 90.5% of 225 C. end point gasoline, in-

dicating a; controlled polymerization with sub-,

stantially no formation or heavy carbonaceous material corresponding to pitch or asphalt. At

when using this catalyst in a continuous experioxide, zinc oxide and zinc chloride. 45 mental plant operating upon commercial propyl- 6. A process for the treatment of gases from one of 95% purity. In the run shown 93.5 parts the cracking of heavy 1nto lower boiling hydrovby weight of the prepared catalyst was used as a carbons to convert the same into liquid hydrofiller in an exteriorly heated horizontal tube. carbons suitable for motor fuel which comprises,

Exit gas Rate of for- 1 passin Percent con- Average H in Yield 0! 8 1 56 figg throug version of Period number ressure liquid pts. 0 F products catalyst entering gas gJcm' pm by weight (155 5 pts by unc lalliz ged to 0ilh(by Weight/h. weigh W618 t) 55 11.3 0.2 110.0 18.6 10.0 87 -11.0 17.0 100.3 0-7575 9.0 11.0 00.5 11. 0 7. 0 138. 5 19.8 10. 5 87 10.0 17.0 102.9 9.0 13.3 oat 60 11.2 0.0 140. a 0 21.0 212 10.0 17.0 234. a 13.8 18.7 03 10.0 0.0 128.2 7607 21.4 20.0 37 10.0 18.0 281.9 15.0 20.3 90.5 10.4 7.0 147.5 M507 21.1 24.3 80 10.0 10. o 270. 1 L 17. 4 20. 7 90. 0 10.0 0.5 136.3 20.8 18.0 88.5 65 Total and average 10. 5 124.2 1,928- 0 15. 15 2'14. 9 90 subjecting said gases while at elevated temperature to the action of a contact agent comprising phosphoric acid, aluminum oxide, zinc oxide and 7 zinc chloride.

'l. A process for the treatment of normally gas-.1 eous olefinhydrocarbonstoconvert the same into liquid hydrocarbons suitable for motor fuel, which comprises subjecting the said gaseous olefin lLvdro- 7B carbons at polymerizing temperature to the action of a contact agent comprising a mixture of an acid of phosphorus, an adsorbent earth and zinc chloride.

8. A process for the treatment of normally gaseous olefin hydrocarbons to convert the same into liquid hydrocarbons suitable for motor fuel, which comprises subjecting the said gaseous olefin hy-- hydrocarbons at polymerizing temperature to the action oi a contact agent comprising a mixture oi phosphoric acid, kieselguhr and zinc chloride.

10. A process for converting normally gaseous oleflns into hydrocarbon liquids which comprises polymerizing the oieflns in the presence of a solid mixture of phosphoric acid and zinc chloride.

11. A process for converting normally gaseous oleflns into hydrocarbon liquids which comprises polymerizing the olefins in the presence of a solid 10 mixture of phosphoric acid and zinc oxide.

12. A process for converting normally gaseous oleiins into hydrocarbon liquids which comprises polymerizing the olefins in the presence of phosphoric acid, zinc chloride and zinc oxide.

VLADMR IPA'I'IEFF.